Smooth Borders
This command modifies the borders of the selected mesh. These borders will be smoothed.
Requirements
Select the mesh and launch the command.
Define the borders you want to smooth. Selected borders are displayed in pink.
Use the options Select borders shorter than or Select borders longer than and set the Length threshold.
And / or select holes by click
And / or make a rectangular selection of holes in the scene.
Optionally, Limit Edge Length defines the maximum edge length of the smoothed borders. You can adjust this value and make a preview to see if the result fits your needs.